Beta 1 integrins in third trimester human placentae: No differential expression in pathological pregnancy

Abstract

Integrins are a group of cell surface receptors that play important roles in cell-cell and cell-extracellular matrix interactions. The expression of trophoblast cell surface integrin subunits changes during placental development in normal pregnancy but the functional significance is unknown. The aim of this study was to investigate the expression of β1 integrins and their extracellular matrix ligands in human placenta and membranes in normal and pathological pregnancy using an avidin-biotin-peroxidase technique. Expression of the β1 integrins was similar in all study groups. Whilst there was some heterogeneity of expression of specific integrin a chains this was not characteristic of defined subject groups, variations occurring within all groups. Two distinct trophoblast subpopulations were demonstrated in the chorion laeve according to differential expression of β1 integrins. Trophoblast immediately adjacent to maternal decidua, which expressed al rather than α2, also comprised the majority of trophoblast in the basal plate; possession of the α1, α3, α5, α6 rather than α2, α3, α5, α6 phenotype may be important in the invasive potential of trophoblast populations. The results obtained in the present study indicate that the integrin phenotypes of third trimester uteroplacental tissues are similar in normal and pathological pregnancy, including pre-eclampsia, before and after labour.